This research will seek to determine if technological innovation developed for the MOD-Series computer system in the 1970's for efficient processing of large numbers of census summary tapes on mainframe computers, can be successfully adapted to the microcomputer environment expected to exist at the time of the 1990 Census. A partial prototype of the mainframe MOD-Series system will be developed and placed with a panel of experienced MOD-Series users from government, industry, and universities for evaluation. The test panel will evaluate the partial prototype for its effectiveness in processing large census files on a microcomputer. If the research is successful, the panel will develop a concept design for a complete microcomputer prototype, especially tailored to the operational needs of typical census summary file users. This design will form the basis for a research proposal for Phase II funding.